# `MingaEditor.RenderPipeline.Classifier`
[🔗](https://github.com/jsmestad/minga/blob/main/lib/minga_editor/render_pipeline/classifier.ex#L1)

Classifies a render pipeline run as a line-patch fast path or a full path (#2287).

The classification is a telemetry and observability tag: both paths run the
same seven stages and emit the same `begin_frame`/`commit_frame` transaction
with the same `gui_window_content`/delta encodings. There are no new opcodes.
What differs is the work the Content stage actually does: on the `:patch`
path, the upstream row-retention cache lets unchanged rows skip composition,
so a patch frame rasterizes only the rows that changed.

## Path meaning

- `:patch` — cursor motion or a single-line edit confined to the active
  window's current viewport. The frame is expected to rasterize zero rows
  (pure cursor motion) or only the affected rows (a single-line edit).
- `:full` — anything structural: a window split/open/close, a resize, a
  theme change, chrome state changes, a forced keyframe, the first frame, a
  content-epoch reset, or a viewport scroll. Multi-window frames are
  always `:full`.

## Conservative by construction

Classification only ever *labels* the frame; it never suppresses work that a
frame legitimately needs, because the row-level content hashing decides reuse
independently. A frame mislabelled `:patch` still renders correctly, and a
frame mislabelled `:full` is merely pessimistic. Per the ticket's risk note,
anything ambiguous classifies as `:full`.

# `path`

```elixir
@type path() :: :patch | :full
```

# `scrolls`

```elixir
@type scrolls() :: %{
  required(MingaEditor.Window.id()) =>
    MingaEditor.RenderPipeline.Scroll.WindowScroll.t()
}
```

# `classify`

```elixir
@spec classify(MingaEditor.RenderPipeline.Input.t(), scrolls()) :: path()
```

Classifies a render frame as `:patch` or `:full`.

Consumes the prefetched per-window scroll snapshots, which already carry the
resolved per-window invalidation (dirty lines, viewport, line count, epoch
reset). Returns `:full` whenever a structural trigger is present or the state
is ambiguous; otherwise `:patch`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*